渭南沋河宋家北沟剖面磁性地层学研究  

ON THE MAGNETOSTRATIGRAPHY OF THE SONGJIA—BEIGOU SECTION,YOUHE,WEINAN

作　　者：胡巍 岳乐平[2] 田新红[2] 

机构地区：[1]陕西省地质矿产局第一水文地质工程地质队,西安市何家村710068 [2]西北大学地质系,西安市太乙路710069

出　　处：《陕西地质》1993年第2期26-32,共7页Geology of Shaanxi

摘　　要：渭南沋河宋家北沟剖面上部为黄土堆积,下部为河湖相沉积;包括全新世黄土(0.8万年)、晚更新世黄土(0.8～13万年)、中更新世黄土(13～73万年)、早更新世中、晚期黄土(73～120万年)及早更新世早期(120～250万年)三门组和晚上新世晚期(250～300万年)沈河组上部。古地磁测定结果表明:B/M 界限位于第8层黄土(L_8)中,M/G 界限位于沈河组与三门组过渡带的上部;贾拉米诺亚带(J)位于S_(11)—S_(12)层段,奥尔都维亚带(O)位于三门组砂层中。渭南新寺剖面作为宋家北沟剖面的补充,可接续沋河组下部层位,古地磁年龄为280～350万年。The section of Songjia-beigou,loess is in its the upper and fluviolacustrion sediment in its the lower,which includes loess of Holocene Epoch (0.8 to 13 thousand years),loess of Middle Pleistocene Epoch (13 to 73 thousand years),loess of Middle to Later period of Early Pleistocene Epoch(73 to 120 thorsand years)and Sanmeng Formation of Early period of Early Pleistocene Epoch(120 to 250 thousand years)as well as the Upper member of Youhe Forma- tion of Later period of Later Pliocene Epoch.The Paleomagnetic study is made.Tt is shown that B/M boundary situated in the upper transitional zone between Youhe Formation and Sanmeng Formation,and Jaramillo normal polarity subaone(J)situated in S_(11) to S_(12) bed, olduvai rwrmal polarity subzone (O) situated in sandy bed of Sanmeng Formation.Xinsi sec- tion of Weinan,treating it as a supplement to Songjia-beigou section,can continue the lower horizon of Youhe Formation,paleomagnetic dating 280 to 350 thousand years.

关 键 词：渭南沋河 黄土磁性地层 三门组 沈河组 

分 类 号：P5[天文地球—地质学]